Question: Simplify the following expression: $y = \dfrac{9k}{5} + \dfrac{7k}{8}$
Solution: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $5$ and $8$ $\lcm(5, 8) = 40$ $ y = \dfrac{8}{8} \cdot \dfrac{9k}{5} + \dfrac{5}{5} \cdot \dfrac{7k}{8} $ $y = \dfrac{72k}{40} + \dfrac{35k}{40}$ $y = \dfrac{72k +35k}{40}$ $y = \dfrac{107k}{40}$